buying a carbon frame..what is ud


Legendary Member
It means unidirectional

Google is your friend

My pave is UD, rides nicely, then I've no other carbon to compare it to (I'd say the Steelie is more comfortable on SW London and Surrey roads)


Mancunian in self imposed exile in leafy Cheshire
The UD you will see referred to on frames, wheels etc. is quite often just the top layer, so just cosmetic. It is not a weaved look it is a flat look. Your other options are matt or gloss weaved finishes the K refers to the size of the strands (bundles) of carbon fibre. I have had gloss and matt 3K weave frames.

jack smith

Über Member
As above its just the cosmetic look, often it has cloudy bits in it from the bonding process or whatever i personally thing 3k looke better


Mancunian in self imposed exile in leafy Cheshire
I believe the weave underneath has a slight effect on stiffness although I suspect you would be hard pressed to be able to id the k cf used in a frame other than what is visible. The layup is going to be more influential in terms of ride characteristics as is the geometry and shape off the frame. A large BB shell and chain stays will stiffen a frame. Aerofoil shaped seatpost downtubes seatstays etc will make the frame more aero. The top end sellers talk a lot about how their frames use certain layup procedures which cheaper open mould frames make no claims on. Would you notice it riding as a hobby, amateur racer, tt'er, probably not much.


North west
The frame I have been informed is made from all ud weave, is this then a weaker strength?


Prize winning member X2
I thought UD was the structural method for building up frames . Matting used for the top lay up and UD for the structure .
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